Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| Glycine | Melatonin | |
|---|---|---|
| Category | Amino Acids | Supplements |
| Standard Dose | 3-5g daily | 0.3-1mg for sleep onset (physiological); 3-5mg for jet lag; 10-20mg for oncological adjunct (under supervision) |
| Timing | 3g before bed for sleep (core body temperature reduction). Divided doses during day for glutathione support. Powder in water has a mildly sweet taste. | 30-60 minutes before desired sleep onset. For circadian phase advance: 4-6 hours before desired bedtime. Sublingual for faster onset. Dim lights 1-2 hours before taking. |
| Cycle Duration | ongoing | Short-term for jet lag (3-5 days); ongoing at low dose for circadian support if needed; extended for oncological use under supervision |
| Evidence Level | strong_human | strong_human |
Glycine is the simplest amino acid with profound neurological and metabolic roles. It is an inhibitory neurotransmitter acting at glycine receptors (strychnine-sensitive) in the brainstem and spinal cord, inducing a drop in core body temperature that facilitates sleep onset. It is also an obligatory co-agonist at the NMDA receptor glycine binding site, modulating excitatory neurotransmission. Metabolically, glycine is the rate-limiting amino acid for glutathione synthesis (glutathione = glycine + cysteine + glutamate), a key substrate for collagen synthesis (every 3rd amino acid), essential for creatine synthesis, bile acid conjugation, heme synthesis, and one-carbon metabolism.
3-5g daily
3g before bed for sleep (core body temperature reduction). Divided doses during day for glutathione support. Powder in water has a mildly sweet taste.
ongoing
Melatonin (N-acetyl-5-methoxytryptamine) is synthesized from serotonin in the pineal gland, regulated by the suprachiasmatic nucleus (SCN) via the retinohypothalamic tract. It binds MT1 and MT2 G-protein coupled receptors: MT1 activation suppresses neuronal firing in the SCN (sleep onset), while MT2 modulates circadian phase shifting. Beyond sleep, melatonin is a potent antioxidant that scavenges hydroxyl radicals, peroxynitrite, and singlet oxygen, and upregulates antioxidant enzymes (GPx, SOD, catalase) via Nrf2. It has anti-inflammatory properties (NF-kB suppression), immunomodulatory effects, oncostatic activity (anti-proliferative in several cancer types), and mitochondrial protective functions.
0.3-1mg for sleep onset (physiological); 3-5mg for jet lag; 10-20mg for oncological adjunct (under supervision)
30-60 minutes before desired sleep onset. For circadian phase advance: 4-6 hours before desired bedtime. Sublingual for faster onset. Dim lights 1-2 hours before taking.
Short-term for jet lag (3-5 days); ongoing at low dose for circadian support if needed; extended for oncological use under supervision
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